Probably my builds is what I did wrong when I started. I never realy knew much about the character so I just looked at the items and picked those that seemed to have nice stats (ex. BF sword on morgana). After a few games of sucking I read a guid and it went so much better.

me as pantheon using ulti to support a teamfight. Why is that nooby? well the teamed died just as i was about to land... you can guess the rest

That's not really nooby; the ultimate is severely hindered with issues that require the player to be able to supernaturally predict the future in order to use it well.

What's nooby is a Taric who, after telling him that you are Grand Skyfalling onto two low HP enemies so you need his help to heal and stun, runs the other way when at full HP and MP during the last 0.5 seconds of your falling channel, leaving you to get owned by a 200 HP Poppy and 150 HP Fiddlesticks.

This one happened to me yesterday, and it was quite noobish. I was pushing mid lane on my own, when their fed AD katarina jumps on me and ults, so I proceed to exhaust her to be able to fight back/escape depending on how it goes... thing is, I mess up with the buttons and end up teleporting to a minion next to her... not to say that in the mean time she shred me into pieces.

Though my Noobiest death must be back when I was level 5 or so, and after a winning streak(can't imagine how) with sivir, join another game, thinking i must be so pro at this game!. So I go bottom lane, and happily go check who is in the other tower. Suddenly pantheon and some other guy jump on me from the bushes(that I should have thought that they were for decoration only) and get totally owned. So i get back angry to show them who's the boss... throw the BB and get into the bushes(yet again) to get equally owned... I think I spent a week running away from any bush in the game!

Last night I was playing while super tired and kept making so many dumb mistakes as Rammus. Everyone would be MIA and I'd be pushing waaaaaaay out there in a lane going "hurrrrr I'm gonna eat this tower hurrrrrr". Enemy team would, of course, pop out and wreck me.